The present invention relates to an improved position servo loop for a robot or automatic machine.
In an articulated modular robot, capable of moving around a certain number of axes by means of a hydraulic motor with servovalve control in each axis, it is normal to use a servo loop to transmit the successive command signals to the servovalve. This servo loop has, as is well known, a feedback path which constantly furnishes to the input a signal corresponding to the position of the robot about the axis considered and thus permits establishment in a continuous manner of the position error in response to a position command and finally to correct this error so as to arrive at the desired position in the shortest time.
The most important qualities of a servomechanism are its stability, precision and speed of response. With these in mind it is desirable to avoid oscillatory operation, reduce overshoots and improve the response time of the servo loop. For example, in a Nichols chart the critical contours are to be avoided.
The present invention discloses a circuit with these improvements.